Nokea
Who is credited with the discovery of nuclear fission?
- A. Marie Curie
- B. Albert Einstein
- C. Enrico Fermi
- D. Ernest Rutherford
Correct Answer: C
Rationale: Enrico Fermi is credited with the discovery of nuclear fission. In 1934, Fermi bombarded uranium with neutrons, leading to the splitting of the uranium nucleus and the release of energy. This groundbreaking discovery laid the foundation for the development of nuclear power and weapons. Marie Curie is known for her pioneering research on radioactivity, but she did not discover nuclear fission. Albert Einstein made significant contributions to physics, including the theory of relativity, but he was not credited with the discovery of nuclear fission. Ernest Rutherford conducted the famous gold foil experiment and made contributions to the understanding of the atom's structure, but he did not discover nuclear fission.
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What information can be obtained directly from the element's atomic number?
- A. Its atomic mass
- B. Its position on the periodic table
- C. Its number of neutrons
- D. Its chemical properties
Correct Answer: B
Rationale: The atomic number of an element represents the number of protons in the nucleus of an atom. This number determines the element's unique identity and its position on the periodic table. The atomic mass (option A) is not directly determined by the atomic number but is a weighted average of the isotopes of an element. The number of neutrons (option C) is not directly provided by the atomic number but can be calculated by subtracting the atomic number from the atomic mass. The position on the periodic table (option B) is directly related to the atomic number, as elements are arranged in order of increasing atomic number. The chemical properties of an element (option D) are influenced by the number of protons in the nucleus, which is determined by the atomic number.
Which of the following structures plays a crucial role in controlling the cell cycle and preventing uncontrolled cell growth?
- A. The centrioles
- B. The nucleolus
- C. The Golgi apparatus
- D. The endoplasmic reticulum
Correct Answer: A
Rationale: The correct answer is A: The centrioles. Centrioles are cylindrical structures found in animal cells that are crucial in organizing the spindle fibers during cell division (mitosis). They play a vital role in separating chromosomes during cell division, ensuring each daughter cell receives the correct number of chromosomes. Additionally, centrioles are involved in the formation of cilia and flagella, essential for cell motility and sensory functions. The nucleolus is responsible for ribosome production, the Golgi apparatus processes and packages proteins, and the endoplasmic reticulum is involved in protein synthesis and lipid metabolism. These structures do not have a direct role in controlling the cell cycle and preventing uncontrolled cell growth.
Imagine you have an element with atomic number 11 and mass number 23. How many neutrons does it have?
- A. 11
- B. 12
- C. 23
- D. 21
Correct Answer: B
Rationale: - The atomic number (Z) of an element is the number of protons in its nucleus. In this case, the element has an atomic number of 11.
- The mass number (A) of an element is the sum of its protons and neutrons. Given that the mass number is 23 and the atomic number is 11, we can calculate the number of neutrons by subtracting the atomic number from the mass number: Neutrons = Mass number - Atomic number = 23 - 11 = 12.
- Therefore, the element with atomic number 11 and mass number 23 has 12 neutrons.
A population refers to a group of organisms of the same:
- A. Species living in the same area
- B. Genus competing for resources
- C. Kingdom inhabiting a specific biome
- D. Phylum found throughout the world
Correct Answer: A
Rationale: A population is defined as a group of organisms of the same species living in the same area and interacting with one another. Option A correctly describes this definition by specifying that the organisms are of the same species and share a common geographical location. Options B, C, and D are incorrect because they do not accurately define a population in biological terms. In this context, a population specifically refers to a group of organisms belonging to the same species, not higher taxonomic ranks like genus, kingdom, or phylum.
What is the unit of measurement for force in the International System of Units (SI)?
- A. Newton (N)
- B. Kilogram (kg)
- C. Joule (J)
- D. Meter per second squared (m/s²)
Correct Answer: A
Rationale: The unit of measurement for force in the International System of Units (SI) is the Newton (N). One Newton is defined as the force required to accelerate a mass of one kilogram at a rate of one meter per second squared. Therefore, the correct answer is Newton (N). The other choices are incorrect because: B) Kilogram (kg) is a unit of mass, not force; C) Joule (J) is a unit of energy; D) Meter per second squared (m/s²) is a unit of acceleration, not force.